In one saute pan combine onion, oil and garlic and cook over low heat until onions are translucent. Remove 2/3’s onion mixture from pan and split into 2 pans. Add one color of tomato to each of the three pots. Add 1 cup stock and ½ cup of water to each pot and simmer until tender. Puree, until smooth, all 3 separately beginning with tomatillo- pour into separate containers. (no need to wash workbowl between colors). Chill. Pour into soup bowl simultaneously (a third hand is crucial). Garnish with creme fraiche, additional chopped tomato, salsa, fresh corn, roasted peppers, etc., and serve.